Method of and apparatus for dehydrating tar



H. A. KLEINMAN Filed March 15 1929 METHOD OF AND APPARATUS FOR DEHYDRATING TAR March l Patented Mar. 1, 1932 nieta HAROLD A. KLEINMAN, or Moninn, iLLiiieis. AssiGNoa To fri-in Gas MACHINERY ooMPANY, on CLEVELAND, omo, A conroaa'iion or oi-iio METHOD OF AND APPARATS FOR DEHYDRATING TAR v Application filed March 13, 1929. Serial No. 346,670.

My invention particularly relates to the separation of water and some of the light oils from a tar emulsion by a process and in apparatus by which, after` each batch or charge 'ofI the emulsion has been circulated and heated, the dehydrated tar and water are intermittently drawn off. The circulation is effected periodically for desired periods of time in a closed circulatory system, some of the evaporated water and light oils being withdrawn continuously during the circulation of the batch, each batch beino dehydrated separately and entirely and fully drawn off before another batch is charged into the separating tank. vThe water and light oils rising to the top of the tar in the separator are also drawn on? intermittently.

In those operations in which the emulsion contains a high percentage of water, so that the remaining dehydrated tar occupies only a comparatively small per cent of the active capacity of the separating tank 1, the water is drawn ofi' and the tank l filled to one hundred per cent active capacity with a. fresh batch of emulsion, without drawing off the comparatively small amount of tar of low moisture content remaining 'from the previous batch. This modification of the regular and normal method of operation hereinbefore described presents some advantages when dealing with emulsion of high moisture content because the moisture content of subsequent batches is much less than the moisture content of the first batch and it might be advantageous to leave a certain quantity of the dehydrated tar in the separating tank. l The annexed'drawing and the following descriptionset forth iny detail certain steps 40 illustrating the carrying out of my improved method and certain means exemplifying an embodiment of my improved apparatus, such ,steps and means, however, illustrating but one of the various processes and but one of the various structural assemblies by which the principle of the inventionmay be carried out.

The drawing is a diagrammatic view of certain apparatus in which my improved process may be carried out and embodying the several elements of my improved 'dehy-A drating means.

Referring to the annexed drawing, I' provide a separating tank 1 which is intermittently charged with desirable-sized',batch-es 5;

of tar and water emulsion, this ychargingbeing effected in any desired manner'and illustrated in the accompanying dra-wing by the valve-controlled emulsion inlet 2 connected to a pipe section 4 which enters the bottom of the tank 1. AThe separating tank 1 is provided with a vertical series of valve-controlled test pipes 16, whereby the water which separates'out in the tank 1 and rises to the top of the tar therein can be tested as to height and intermittently drawn off, as desired. Through the medium of a suitable pump, such as illustrated by the lcentrifugal pump 3, and by pipe connections 4 and 5, the batch of emulsion charged into the tank 1 is passed through a heater 7 supplied with steam, the actual passage of the emulsion through the heater 7 being accomplished in any suitable manner, the means shown in the accompanying drawing being illustrative and consisting of a coil 6 connected to the pipe 5 at one end and connected at its discharge end with a pipe 8 which feeds into the top of the separating tank 1. Thev heater 7 is steam-heated in any desired manner and I illustrate in the accompanying drawing two or three expedieiits for effecting this operation. Forinstance, the exhaust steam from the pump 3 is supplied through the conduit 13 to a pipe section la' and thence conducted to the heater i casing 7 Exhaust steam from an outside source can be fed to the pipe section 14 which is valve-controlled beyond the connection of the conduit 13. Live steam can be fed to the pipe section 14 through the valve-controlled conduit 15. The valve control for theV live steam connection 15 consists of a valve member 21 Which acts automatically to furnish the proper discharge pressure.

The tank 1 and the heater 7 and the various pipe sections mentioned form a closed circuit by means of which the emulsion is circulated or recirculated for any desired period of time. Preferably, the actual discharge ot the heated emulsion into the top of the tank 1 is effected through spray openings y17 formed in a vpipe section 9 located inthe top of the tank 1 and connected to the discharge end of the pipe section 8.

@In ypassing through ftheope'nings 17, lthe emulsion is broken up, vand the'tar is separated out from the emulsion and goes to the bottom of the tank 1, the Water remaining on top of the tar. Thetemperatureat Which the emulsion is sprayed from the openings 17 ima-y vary over a considerable range but ifs such as to effect the vaporization of part- .of the YWater and light oils underthe tempera- .ture and'pressureexisting inthe tankl. ,For instance, the :emulsion :might leave the -ihe'ater 7 yat-aboutV 227 degrees Fahrenheit, ithe Ypressure being about live pounds,'the .pressurein v .the top of the tank 1'beingsubstantially.at-

, .grees Fahrenheit.

.,mospheric, andi-the temperature :in the top of theV tank 1 beingapproximately 212 de- 'Fhus Vpart of :the Water .and light oils vare evaporated fasrthey pass .-throughftheopenings 1:7 'andfpassolifthrough ythe pipe v`,connection 10 into a condenser l11 zto vWhich cooling vWater Vis supplied. The condensed vapors `pass 'out of ythe 'condenser 111 .through'a -pipe 19 to the inlet 20 of the tar .and liquor separator (inotishown) ,-Whichlatlter,as is Well-known tothose skilled :in'the yart, receives the overflow 1from the -seals,con-

densers, .scrubbers, tar eXtractors, feto., of 'a Water gas plant. A Siphon -seal 23 is provided inthe .inlet ypipe20. However, ii'the pressure vin the tank 1 `is reduced toa point 'lower than substantially atmospheric, the temperature at whichfthe emulsion fleuves `the heater `I7 yand passes 'through "openings :17 y iu-st -be such that part of the vrWater 'and light-oils -Will be'evaporated .under the temperature and pressure 'that is maintained iin the tank l. For instance, the pressure'in'th'e -tank 1 Kcan -be Areduced below atmospheric pressure through the medium of the 4valveycontrolled pipe 211and the pump'22, '-andthe vaporization vo'i' part of :the YWater 'and light ,oils.obtained, even ithetemperature YVofthe Y ,emulsion passlng'througa the iopenings :17 lis below 212 degrees Fahrenheit.

The circulation iscontifnued until the-de- "12 .siredfseparationof the Water fromthetar-is reflected. and then the pump-3 'is'stoppedland .thefemulsion remaining' in the tank =1 :allowed to settle. After-settling, the Water isdravvn .oii from the top ofthe emulsion inthetank 1 'j ,fand-.the 'remaining tarcontaining .but 'very by my improvetlmethodand'fin my improved apparatus, batches of emulsion are periodical- `ly chargedintothetankland a Whole batch age of -Wat-er.

little Water is transferred to a dehydrated tar storage tank through the medium of a valvecontrolled pipe 12 connected to the pipe section 4. This pipe section 4 is also valve-controlled, between the pump 3 and the connection With the pipe 12, as shown. The Water upon the top of the tar in the separator l can be intermittently drawn off, as desired, through the test pipes 16 or other suitably located larger discharge means.

rEhe separating tank 1 is then-partly filled With-another batch oflemulsiontto thedesired leveland the afore-described process repeated.

VI direct particular attention to the fact that Y 'is separatedto the desired extent into the dehydrated tar. and Water, and the separated tar and Water drawn oft, before another batch of yemulsion charged finto the :tank f1, v except orr the modification .-hereinbefore described -When the :emulsion 'contains a .high percent- The dehydrated z'ari'is :drawn oli" at the end ofthe circulating `:and settlingwg period Itor the particular batcl1,;and the fseparated Water `is drawn ofi' 'rnterniittently, uis vdesired. 'Part of :the Water and .flight -nils evaporate :andare-:taken oftcontinuously from the separating-tankzduring thefcircuhtingcrp- .is eration. A

VVhatIzclaimis: 'l

.1. .A method of dehydratingftarfcomprising, recirculating a batch of; the vemulsion eof tar fand .Water through a :closed :system idf-..100 which one portionrconsists'infa.separatingsector, the Water and light oils .being Aisep'arated Y ffrom the 'tar in saidseetor.; fexterviorty steamv'heating vthe vemulsion fea-ch time it zpasses through' anothersector 'of fthe system, aand -`be- 395 io're =it reaches said-sep arating.- sector, thezsysytem being maintained :at ya :temperature :of

substantially 212 D `F.,the=emulsi'on ileavingithe :heater at a temperature .'higher than lthat :at -Which Water 'boils under the temperature ,zand :gno

Ypressure 'existing inthe separating sectorfof 1 the system; permitting Ythe vemulsion thus treated .to settle `in the :separating sector after the-.circulatoryoperation continuously 'tor, 4the Water and light oils being separated kfrom the tar in safi'dsector g -exteriorly steam- 1125 heating the emulsion each time it -passes 'through another sector oit the -system,-afndbe 'tore' it reaches saidsep'arating sector; spraying'the heated lemulsion into 'the separating .sector of the .fsystem fso as fto frbreak iup the 3130 emulsion and separate out the tar therefrom, the system being maintained at a tempera'- ture of substantially 212 F., the emulsion leaving the heater at a temperature higher than that at which Water boils under the temperature and pressure existing in the separating sector of the system; permitting the emulsion thus treated to settle in the separating" 

